Fibromyalgia: a study of family history of depression

Previous research has suggested that some fibromyalgia may be part of an "affective spectrum disorder," pathophysiologically related to major depression. To examine the suspected association between fibromyalgia syndrome and depression, we conducted a family history study of depression among the first degree relatives (parents, siblings, and children) of two groups of probands with fibromyalgia, one with and one without a lifetime history of major depressive disorder. We tested the hypothesis that depression in patients with fibromyalgia is associated with a family history of depression. Major psychopathology in the probands was assessed with the Schedule for Affective Disorders and Schizophrenia and diagnosed using the Research Diagnostic Criteria. Forty fibromyalgia probands with and 14 fibromyalgia probands without a lifetime history of depression were interviewed about their parents, siblings, and children using the Family History Research Diagnostic Criteria format. Odds ratios were calculated, comparing the proportions of relatives with a history of depression in the two fibromyalgia proband groups. Lifetime histories of depression were found in 18% (n = 16) of the relatives of the probands with fibromyalgia and depression and in 9% (n = 25) of the relatives of the probands who did not have depression. Probands who had fibromyalgia and a history of major depression had more than twice the odds of having a relative who had depression than did the probands who had fibromyalgia but did not have a history of depression (odds ratio = 2.17 (95% confidence interval = 1.02-4.47)). These results suggest that depression in patients with fibromyalgia is associated with a family history of depression. Thus major depressive disorder in patients with fibromyalgia may be attributed more to their familial predisposition to depression than to a reaction to the pain and disability associated with fibromyalgia.